The present invention relates to a calling method and a calling apparatus in a telephone set linked to a service network capable of informing of the telephone number of a caller.
There have been provided various types of telephone sets linked to a service network and having two or more call display modules, including a PBX linked by wire lines to a plurality of telephone terminals and a combination of a master unit linked to a service network and sub units connected by radio lines to the master unit, such as a cordless telephone system. It is now known in the cordless telephone system, as PHS systems have increasingly been utilized, to have a digital cordless telephone master unit connected to commercial PHS telephones as digital cordless telephone sub units. As the PHS telephones are connected via the digital cordless master unit to a cabled service network, they can favorably be used by users as private cordless telephone sub units in both public and private modes.
In such a conventional telephone system, a calling method in response to the receipt of a call from the service network is based on displaying the call on substantially all the call display modules. More particularly, as the call is received from the service network in a telephone system having a PBX connected by wire lines to a group of telephone terminals, all of the telephone terminals start ringing almost at once indicting that the call is received. In the case of a cordless telephone system, the master unit and the sub units in standby are simultaneously triggered for ringing or vibrating to indicate that the call is received. Also, when the PHS telephones are used as cordless telephone sub units or dedicated to only private telephone communications, they, as well as the master unit, start simultaneously indicating the existence of the call upon the call being received by the master unit.
In such a conventional telephone system having two or more call receiving modules with a call display, the calling is made by allowing all of the call displays to indicate substantially at the same time that the call is received. It is hence necessary that any of the telephone terminals responds to the call and after identifying the destination of the call, transfers the call to the target telephone terminal. Accordingly, the disadvantages are that the transfer is troublesome and that the receipt of the call is known by users other than the user to which the call is made and secrecy about the communications is impaired.
It is thus an object of the present invention, in view of the foregoing disadvantages, to provide a calling apparatus and a calling method for a telephone set which can minimize the troublesome transfer action and protect the secrecy of the communications.
A calling apparatus in a telephone set according to the present invention comprises: an interface circuit for connecting to a service network; a call detecting means connected to the interface circuit for detecting a call from the service network; a telephone number detecting means connected to the interface circuit for detecting the telephone number of a caller from the service network during the connection; at least two call displaying means for indicating that the call is received from the service network; a telephone number memory means in which data for determining the display of the call on a selected one of the call displaying means depending on the telephone number of the caller is stored; and a controlling means for, when the call from the service network is detected by the call detecting means and the telephone number of the caller is detected by the telephone number detecting means, comparing the detected telephone number with the data stored in the telephone number memory means and directing the desired one of the call displaying means designated for display of the detected telephone number to indicate that the call is received from the service network, whereby only the call displaying means dedicated to the telephone number of the caller received can be initiated to indicate the call.